This study deals with the genetic determinants of human glial neoplasms and other human cancers utilizing physical chemical, cytochemical, chromosomal and electron microscopic techniques. We propose to quantitatively analyze the number and types of satellite DNA in human glial neoplasms, in neoplastic cells not of neuroectodermal origin, and in normal human cells in order to see if there are specific DNA components that are amplified or decreased in the course of malignant transformation. These DNA components will then be isolated and applied to cytological material to determine if there is abnormal localization of these molecules in chromosomes of neoplastic cells. The redundancy of these DNAs and their relationship to heterochromatin, euchromatin and nucleolus, as well as to the cell cycle will be investigated in order to further clarify their cellular function. Normal cells will be transformed with chemical carcinogens and viruses, and the ensuing chromosomal constitution of these cells (vide supra) will be related to their biological malignancy as demonstrated by experimental studies with tissue culture and heterotransplantation.